Isopropanol has industrial use in the manufacture of a wide variety of chemicals including isopropyl amine and various ethers. One of the industrial processes for producing isopropanol is by the hydrogenation of acetone. In these processes an acetone containing feedstock is contacted with hydrogen in the presence of a hydrogenation catalyst to produce a crude product.
It has become an objective in some of the processes to employ the reaction product from the hydrogenation of acetone without purification for the synthesis of industrial chemicals. In the manufacture of isopropyl amine by the amination of isopropanol, it is necessary to convert substantially all of the acetone in the hydrogenation reaction product in order to prevent amine contamination. Achieving high conversion of acetone to isopropanol and excellent reaction rates have been objectives of these processes.
The following patents are representative of processes for the hydrogenation of carbonyl compounds including acetone:
U.S. Pat. No. 5,081,321 discloses a process for the catalytic hydrogenation of acetone by feeding hydrogen and acetone in liquid phase to a reactor having a fixed catalyst bed from its top to form a cocurrent gas/liquid flow and maintaining a trickle bed state. Raney nickel, e.g., Raney nickel alloy (Ni/Al) as well as copper based catalysts, e.g., copper-chromium; nickel based catalysts and the platinum group catalysts, e.g., palladium, ruthenium, rhodium and the like, are suggested as candidates.
U.S. Pat. No. 5,449,838 discloses a two step process for generating isopropyl-t-butyl ether wherein the first step resides in the vapor phase hydrogenation of acetone to isopropanol and the second step resides in the conversion of the isopropanol reaction product to isopropyl-t-butyl ether. In the first step crude acetone is passed over a bulk metal catalyst comprised of a nickel-rich catalyst characterized as having the composition, calculated in mol %, of from about 60%–85% nickel, 1%–30% copper and 0.1%–6% chromium with the preferred proportions being about 65%–78% nickel, 10%–20% copper and 1%–3% chromium.
U.S. Pat. No. 5,495,055 discloses a process for the fixed bed hydrogenation of acetone to isopropanol using a ruthenium based catalyst.
U.S. Pat. No. 4,182,721 discloses processes for the hydrogenation of carbonyl compounds using a Raney nickel catalyst having molybdenum adsorbed thereon. The patentees noted that conventional Raney nickel catalysts are not entirely satisfactory because of their relative inactivity.
JP 62-012729 A (abstract and translation of examples and claims) discloses a process for preparing isopropanol by the batch hydrogenation of acetone at a pH 7.0–8.2 over Raney nickel catalyst at 100–160° C. In one example, 300 ml of a mixture containing 66.4 wt % acetone, 33.3 wt % isopropanol, and 0.3 wt % water is hydrogenated over 15.7 g Raney nickel at 150° C., 370 psig, and pH 7.6 for 30 minutes to give 99.3% conversion of acetone and 100% selectivity to isopropanol (IPOH).
U.S. Pat. No. 5,684,215 discloses a process for the preparation of an alcohol by reacting a carbonyl compound, e.g., a ketone or aldehyde, with hydrogen over a supported catalyst containing nickel, aluminum and zirconium at temperatures of from 60 to 150° C. Both liquid phase and gas phase reactions are described.
U.S. Pat. No. 2,614,107 discloses a process for the reduction of carbonyl compounds such as aldehydes and ketones using synthesis gas as the reducing agent. Example 5 shows the hydrogenation of acetone to isopropanol under liquid phase conditions using a cobalt acetate catalyst. Other catalysts suggested as being suited for hydrogenation include iron, nickel, ruthenium, rhodium, platinum and palladium.
JP 03-141235 A (JP 2834495 B2) (machine translation) discloses a process for hydrogenation of acetone in which isopropanol is circulated at 800 ml/h and 100° C. to a reactor having a fixed layer of Raney nickel catalyst. Acetone at 79 g/h and hydrogen at 66.6 L/h are continuously fed to the reactor. The reactor pressure is 20 kgf/cm2, and the reactor temperature is 106.8° C. Acetone conversion is 99.8%, and isopropanol selectivity is 99.9% vs. 70.5% acetone conversion and 92.2% isopropanol selectivity when the hydrogenation is conducted without circulation of the reaction mixture.
JP 03-133941 A (JP 2786272 B2) (machine translation) discloses the hydrogenation of acetone in a fixed bed using a Raney nickel catalyst. Isopropanol is produced in 99.9% yield with 99.9% conversion of acetone.